// 函子
class Container {
    static of(value) {
        return new Container(value)
    }

    constructor(value) {
        this._value = value
    }

    map(fn) {
        return Container.of(fn(this._value))
    }
}

// Maybe 函子
class Maybe {
    static of(value) {
        return new Maybe(value)
    }

    constructor(value) {
        this._value = value
    }

    map(fn) {
        return this.isNothing() ? Maybe.of(null) : Maybe.of(fn(this._value))
    }

    isNothing() {
        return this._value === null || this._value === undefined
    }
}

exports = { Maybe, Container }
module.exports = { Maybe, Container }